Sum Array push values, before a 0 javascript

I'm trying to take the value of an input and keep it in an array. I want to detect when the user text 0, and I want to sum all the values in the array before the 0.

Here is my code:

<form id="demo">
    <input type="number" id="lala">
    <button onclick='funsuma(this.form.lala.value)' > NO <button/>
</form> 

<script>
    var global = [];
    var suma = 0;

    function funsuma(valor) {
        global.push(valor);
        for (i = 0; i < global.length; i++) {
            if (global[i] == 0) {
                suma += parseInt(global[i], 10);
                alert("Es 0, tu suma es: " + suma);
                return false;
            } else {
                //alert(global[i]);
                document.getElementById("demo").innerHTML = "<input type='number' id='lala'> <button value='Envia' onclick='funsuma(this.form.lala.value)'> NO <button/>";
                return false;
            }   
        }

        //console.log("global");
    }
</script>